The present invention relates to a method for aiding the design of a system architecture. The design of system architectures notably relates to the field of system engineering. The systems to which embodiments of the present invention applies may be hardware systems, software systems or systems combining hardware and software. Embodiments of the present invention may be implemented within the framework of the realization of a flight and navigation system of an aircraft for example.
The objective of the construction of a system architecture, whether it be hardware, software or both, is notably to decompose the system into a certain number of components which can be sub-systems, software components, calculator, electronic processing boards. The components of the system are subject to the same constraints as the system. The constraints applicable to the system may be:                functional, such as: functions performed by the system, implementation conditions for the system;        non-functional, such as: expected performances, an operational availability, safety, and integrity of the system that corresponds to a confidentiality to be guaranteed and to a resistance to external hazards, a maintainability, but also a facility for integration, for re-use and for development.The maintainability of a system is notably the ease with which it is possible to carry out preventative or curative maintenance on the system in order to guarantee its reliability.        
The construction of an architecture best adapted to satisfying one of the constraints of the system is very often not well adapted to satisfying the other constraints of the system. For example, precautions in the design of an architecture aimed at promoting an integrity and an availability of the system often lead to a degradation of the performances of the system. The modification of the architecture designed with respect to a first constraint in order to take into account a second constraint is costly on the one hand and, on the other, leads to an architecture maladapted to the other constraints. It may notably be impossible to adapt an architecture, designed with respect to the first constraint, to the second constraint without degrading the compatibility with the first constraint. The first and the second constraint may then seem to be contradictory.